Cancer is one of the leading causes of death in the world. Despite improvements in prevention, early detection, treatment and survival, the American Cancer Society states that breast cancer is the second most common newly diagnosed cancer and second leading cause of death among women in the United States. Breast cancer is a cancer that forms in tissues of the breast. The most common type of breast cancer is ductal carcinoma, which begins in the lining of the milk ducts (thin tubes that carry milk from the lobules of the breast to the nipple). Another type of breast cancer is lobular carcinoma, which begins in the lobules (milk glands) of the breast. Invasive breast cancer is breast cancer that has spread from where it began in the breast ducts or lobules to surrounding normal tissue. Breast cancer occurs in both men and women, although male breast cancer is rare.
Targeted therapy is one treatment option available to patients. Target therapy may involve the administration of drugs or macromolecules such as antibodies that are selective for cancer cells and leave normal cells relatively unharmed. Conventional therapeutics for breast cancer are limited in large part because it is not always possible to establish the efficacy of available drugs without trial and error. Further limitations include one or more of the following: high production cost, drug resistance, complications resulting from chemotherapy; and/or safety issues related to the use of the drug. Alternative approaches are needed for improving targeted therapy for breast cancer.
Treatment options for breast cancer include surgery, radiation therapy, hormone therapy, chemotherapy and targeted therapy. Treatment regimens are often determined based on the stage of breast cancer, whether the tumor has hormone receptors, whether the tumor has too much HER2 protein, general health, and other details such as the size of the tumor in relation to the size of the breast, or whether the subject has gone through menopause.
Many therapeutic agents and combinations of therapeutic agents are used to treat breast cancer, and a challenging aspect of treatment is determining which therapeutic or therapeutic combination is most optimal for treatment. Clinical studies continue to compare the most effective treatments against something that may be better. Common therapeutics used for early breast cancer include the anthracyclines (such as doxorubicin/Adriamycin® and epirubicin/Ellence®) and the taxanes (such as paclitaxel/Taxol® and docetaxel/Taxotere®). These may be used in combination with certain other therapeutics, like fluorouracil (5-FU), cyclophosphamide (Cytoxan®), and carboplatin. For cancers that are HER2 positive, the targeted therapeutic trastuzumab (Herceptin®) is often given with one of the taxanes. Pertuzumab (Perjeta®) can also be combined with trastuzumab and docetaxel for HER2 positive cancers.
What is needed are methods and compositions for determining the selection of effective therapeutics for treating cancer such as breast cancer, and methods for treating subjects with cancer.